SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b58be39daa3663089711b4a1f93d4210830294fc01f346df53b6dea18f0817e' 
  AND token = 'NcXPhUvozirEMdqqPrWQ4SBFJGYnc+SZwa3lDSkRQBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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