SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393e95c07d197e44eb5145c0e768a82e605abfc0d9590525affafda521363cc3' 
  AND token = 'NhvkMPu37Ra2wo2iTxsAcZ20DWFswR73/Fs5MiECqy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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