SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38120302a5d1d1bf0dab765680c0d599a239f3bf664ff7230f8a37de388ce39' 
  AND token = 'nip9F2+gF96+F91u7DzGgcBsOmLNjPcrOh+phw6xz1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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