SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27beb3784bf7d038a6b6008af9e76fef4d7c518cb2662464b782ffe139e86db8' 
  AND token = 'z1Ih1+p6oJuswQ5I6Fo4EO8Jvf037lC0i305oiOk2Co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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