SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b317d7691b4656ed57517cde9117d7f70456667b24ed74b8b03fdd15782dde05' 
  AND token = 'cilgmxmRQ47HOkV42AnJRACPDjjK+EKs58FitXFF8J0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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