SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f508356bf08aeb6c70298b57f1797b75cfe6cf8378b4c5e430598cff3e37431' 
  AND token = '5wOlCEyUFJCavYgKFHZyERpv/3tY8fYDUy2RUpTptQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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