SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4c61103715689845a579b000eb1a04a41f8eebe17220f721dd1725ec97a399' 
  AND token = 'V6DhhS2XnqGYYYEFYqs+vLSww/OrpMwssIW/OnNVvSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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