SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ef0627a2b85007f8eefccd88944e41287b13e7dc7b5984039e85de759f5cbb0' 
  AND token = 'vHqFXFWq/StIjjFuGINEZ2mehzwuxDqEHRz5luYE/Gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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