SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d711abfe60bec6420cfacf4e7b010a84dbf638e70ee029b47bae65a629926d' 
  AND token = 'GsRpCkZhe+pbE06NEJeInGAokDF/Ir6iIbfmnPg0rDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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