SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404dc0cffedf5fa9298c4d6d09877259394a0153adc69dfc8d4cf1593470bc8a' 
  AND token = 'oPlwyr0NfI+dtrzYlSOBFVyAI6HK6se0EW+Xr5Yg42I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}