SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b46c3acd62a53f97f19810fbe5f95c990e9db5f07d3dc53a15a58c342b29d26' 
  AND token = 'TdsIwJU+JKM24dywCxapcvpYjdqvgXvS99A7kXIu+c4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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