SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a146123466f9e831b488a53fc0e384195934a5c717dc4d211ae7026b9abacef9' 
  AND token = 'SpCnKadgahQisuk9kBRoVcCTz9srY0HQLc+9ei9lmN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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