SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02bcfb2d00fa52be1d6a5016198017586bf9c9ccef03370d1e6a860816434b53' 
  AND token = 'TEjsBclw2EDSAo8pp0P371p1fO6cqh8KX1FqjAKz8RQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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