SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ad5d7ded0bba6e834dc39567ce8bd7bdb2c3f36e24910d71b96209d6198cabc' 
  AND token = 'AzFBPY+KJI2Hp2yqKzP4TJbA+J/5fDjaBHnWRGX7l8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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