SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb90d2adab24217cf2796c1236f521550d257dedc3c8b67a40cdcd80d0e7769' 
  AND token = 'uPfJya5ftZqZ7WA+3HadujdT36XNSHghrafQ6ZZjtDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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