SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c449eb8c650d6533260d91b79cf68d4fd43bed41d977ac9f31bf9085a9af3e1' 
  AND token = 'eqkBwTaK4x2u2Jztlz2EnOpgLn9cYv1HaLijglYvo0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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