SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b66195b4c05ac348ecdec4085149f0fb598e686a8ee0dada45b057af958fb7e' 
  AND token = 'jE3dKRyS3L6XpR7q1diJ7Vc+cPlNMkmvUh+EVkuONTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}