SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '870ffa60cee999f12c91ccd6ba1009fc78115c40698d69880708964ed157ce47' 
  AND token = '/+1rghfctB24zZnJ3LFy1ITXtf1wbkIoe53cjhWLR/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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