SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77c59d83da1a7680d630c2e44b766c6c7c36060278e2fe67c53759f415232cc5' 
  AND token = 'iNxAdzq79GGPY9wagwKhpSyjq0LU9tdcGZHYSs/jxmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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