SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bde08ec4be61bfc039e68ddedbcb7e57c198545882382414253c2114ddf1d402' 
  AND token = 'mWTfNgZhIA+y/Z32PqASFlPiHr32zPtHEi53bLKZ1NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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