SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70427ec58ffc9ba13a4e53106793bb5709fd36ae6250846c5f7d9a18798585b2' 
  AND token = 'yO6HJPBaP1hR2WkZseL+BVRw6mZw6F+dGl57eudePzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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