SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '909e8366dedea000401e1d10ece20705891659243b3552cef3b0c452af463ad9' 
  AND token = 'iKJYlwqmUeHLcEtNdQmQP0+sr+nCS/ixf5E6AtBDXbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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