SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd752c1c6e9edc61b215270dd528612fd75dd4f10f76825b9bcab89d622da6c08' 
  AND token = '/uPxIoaCUWzhEbe956b5fmAS4JymDX23O8vhd73sa8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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