SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35acaf1cb15763f48e733add30e6b593fa5fedabe5fd04ccdbc4764f424f83f9' 
  AND token = 'Hv/y16/U3mlvdfk09JMDub0hprzx0u0EmItaGUngStw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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