SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6a6591430566271a293ac4fdf938b7b62f5892ecdad7173a49274d169b10c04' 
  AND token = 'Unp+7VBGQ4pGrHQbiURRQ38/LLAHABw9/Fekj4p0+fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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