SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd691de92cd37cd260245ffb8b32931ea2a68b122fa5f8cb9eeea85c7d17e3017' 
  AND token = '+PPMQ6iVOov/uDNhGbp7yYSY7Sgo8IYfP49FqXIjWYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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