SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f0304b51972b2ab4b5063ecbef1aceaaeee7cbd5b289189ab1bf01b5d5d3082' 
  AND token = '43AMHYjB2uFDN3huadMRsvUQhexwIODZGGscNCE3DL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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