SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '470f77a0eafe8596025903d6da1b38d88c463525d6303be8a29de42fe6fc2d60' 
  AND token = 'p0oUkr4ezLpH4f8Eu1RXyg+bTjawgr4ej24kXyJWegM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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