SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc37321e02736068c16ba9d0d55430532b9f95b7e52c2140ae26713ebf74a145' 
  AND token = 'wBUVaIibhsMph2ELAh7BOTueGk5OANFr33ezLXxfTkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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