SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4be947c7a43df467d39438b06e643c5b30d0e21d5de07f04bb3507f25e818871' 
  AND token = 'sJ+WTi4MywtZCMBC3M49NM2vJ64b/eQjrViFk5BKWdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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