SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3c20abdb37d81c83725a32ecb16b7f745acb3c047ff879da1b982f4cbe8db33' 
  AND token = 'w9Z77uxPYohULgO6fstirnim5bZvgCLPGleB7+CtmvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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