SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01a3f6b3e394378d05d68cd70fc6bb3865c4da3d2a2ff984f127c95cf750c241' 
  AND token = 'yPXQsjxtBuZJe6gK0bJfEs2lGKIFYcFJOwHTRtiI4sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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