SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a98d3c7dfa068b7f101612a41a00fba5614e1075d9d924241544762c62fc2149' 
  AND token = 'ymgROqW7a2M4wZ05HgoYcTNryjAvvGToACHZGEETSJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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