SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2c9c2efecd6b252bb96a9cdb995922a36eb99756ffeb66d24abaffd17da2eac' 
  AND token = 'AsmJQbIcuOQnVBr/7AQk/CPOEus4uj4xGvu36ZFt4BA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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