SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd549b0af83b154ce4dc822fa947f9f050d6bf20cb29de2c978ddfcff43b5b3de' 
  AND token = 'RzncNhMo8u0vliW1Fm7vA/yiAQrkCTlgrm07gBVy+Uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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