SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2bb0c1346b85e2ff35ca938054b360cf42393013bb0f3717b3e0a2710e8849a' 
  AND token = 'HOSg7phy9NmYsOUQg3z1RdnZxwnJNYwq6HVEYLm/Fxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}