SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f72ebcfcb6c3cdaceeb491e7f78bb5eeb1b95f36f6db394b3f2b51ed7bd7336' 
  AND token = 'ovRTickh1bLsmHx9KRtXfR2s1jePeDJusPAN6253+As=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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