SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78658ae46eadf9fd6d0f0e241680843adae0edadf7e88849975938f374dec99f' 
  AND token = 'u5Dolw/BfAGGH34dQhi9wReWKlM5byO97Ah5l8X5cNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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