SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da90fd025fdf4b4201b2a9c5a3d3815524575f3dbe26b8f848b6a8ceaf47b697' 
  AND token = 'eT3cGk5DD+QXmUXR6/1kwmjCjlUj/AiroW5VYB32dq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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