SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a8c6c31779de0ed3edb48db294c3fe8d233c810b51bbcea405fff6c8e71636e' 
  AND token = 'MEV1/uf2Im5UtSmKGxSjRWpLZtXg7MSofgtGzqZhDNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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