SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23d1726c55364b114b423f85fd0c8e6ec85678da3685721ca517a66dd95d465d' 
  AND token = 'bAUu77mZLQOV88a4IMORQm2IFkmM6WeN5ucbrMliCKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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