SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fb1aa823640572fce19ca3f60ace4dceaf1d75261a0162159eaadaa329cb7b6' 
  AND token = '1KrjgQuxiorUVZGBsURg4kiED4colaaMhgCO06DK3aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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