SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed344ed708549b0792aa3b0c6a809d33721786db00995fabc014d8959b4bb234' 
  AND token = '7VrT2jLJ8rCc/VEP/uvtS712s1q6BkLWAOwaVhqYJCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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