SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70287b450d957a4851cc6712ca1765378457a07ab26d15e40efc2e06f3a5f3c8' 
  AND token = 'I8FRw1K4MkAZOkl+JlHC1VDEHx1NXhxvkXmg3BNqz1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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