SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3453449ceb42d08eca9732a710c9fb52c2e2884b560dd98c295bfca2143a576' 
  AND token = 'JTTqtrHL+kJclnhNht+YohANxzvDCG6SbjWkSgDJaCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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