SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '714aac813dff196705c63751c26e61247ed4dd34a7763f3d5fee4364dace2689' 
  AND token = 'H/16yOnHc9PHryzmtNGv/qUuYQifakDX356oG3zFPtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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