SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea47ebc36c205d3bd262b1552e01ab047719c0dda4dbb433a067d2ef77a39502' 
  AND token = '6mY1jVLYKGdTUqvnomUAsTIJeiFn0+dofbKq4wMOnoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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