SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd435c588b376dcf063230d90afe1c8f08b9c53091bb90f3e0ac53cbff14a6b' 
  AND token = 'IflgZ6R1d5N/sBy7x2pZEkANcRz0q0nPw58L53NA83c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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