SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9be5cefdf2ade6a9c7183f88916bc6753d054b51ffb259933c47923c40ab10a' 
  AND token = 'n4YacTErUm6+CeyFgfZLEcl8CDS/JRGIaPJHB2KJOOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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