SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b436cfdd75fcf198b4177fa47e35975e8be3609708d69a7b97df9068315e96fd' 
  AND token = 'QssLej4BwV/nHuWWHXArhgGkKLRpI1es8CPjL6njl7E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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