SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '793e93c6596783d1584e2611d83b22198747fa8ae2b5f7bce70ea042d8df84fa' 
  AND token = 'IG4bW7PWGUW9J/uJLMTfdBtlmktEPh+bqgwYXd+U8fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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