SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869ec7d9d728a7cd8c03f2ddc786ad3a23a8222c8c60e8f12576e670a39e337b' 
  AND token = 'uveJPGVRjdlObtXuntOj7YQrtgeRroegezyfPcFqt6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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