SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f2814b81bcfbe75112ba6659375864812071a1ca4c92d3edc18ac2fd2495a08' 
  AND token = 'mM4D4AMH0+ye3nLKSsw2cPbucUSrdM6BOa71PccZ9js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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