SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16068b85532ace8bc192cfc9384e3541b5cc12bb8be7cca6e6503c546861622' 
  AND token = 'rihQG4DjN22IP+MeUherfNQ61Xo4gwHAKDVpzlUdOOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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