SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '14f36c14f2ec57bf2b0b140b4694f05c2911838538b4f0bcb3c60c001d890d25' 
  AND token = 'XSPcubSlvZOiCImI6Wx+DwkAg2PjlKPzS6giFHB4JHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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