SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1aed485786024906394a328839f32c60d856aaf5ba59e76e9a0543d60ad318f' 
  AND token = '+rtFWYPKTbte2SozNKKB6QtYpaGtHJBr7fgW4OUlT/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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