SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77c5e51f8740632eea3140434170105866c6cff3efe96264cca5d3b308004226' 
  AND token = 'EPXyr3CKvokkQGUFVhrEFraNdnRN+qxXBTfDc3KG9vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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