SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ae8c2283797dd489969690a114fa00ee7bb9b39c6198598ffe7f7e24f15b651' 
  AND token = 'vheJf6qfkcyMR5uPmEjEHrEQULJ/fudZ7l0o7+EPgdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}