SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecbab3c7975af710bad767574a3c70e9528b69f1aa40fd1609078ae28bea5292' 
  AND token = 'm55Iku6zzctUIezM2DdVZ04PZSXARNLAqTRb0MsgSgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}