SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09f321acc0aae8eadefcd80980634e6e41a5bdeeeb4843803a45be507f110981' 
  AND token = 'REwgUYtuWfyck2yKJZNEZukMeEZIRVxT0TBjuGSK3Co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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