SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8137a08b3aafb88e2bf11a3ada7545c741086bed998fd150795257f0896ca55' 
  AND token = 'r09jraHa4hbR0uFb+gcAf19FOMd+4UN731Jamjxef8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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