SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4a733fccf77782b409a1d44be499cf0298fc4b573ad7e57a42448ad60b48341' 
  AND token = 'ijqtpxwaTcdE4ewwEd14Pqd14cutPG3WYqOsXef5mMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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