SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee82f957a201dc1480dc5d136683c6ad0db21362c178aac73aa9b6e31b455355' 
  AND token = 'gpGXSmYNplRf/ySJJcrbWHCdofhPZy1t10ldqmqQUks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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