SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '897e7457201f7702f15c52a69347c32b22a86b17a7474e389962bee71905e585' 
  AND token = 'srfHM5S8hwSHQDLWsHupVCu/BM65ox7gTzRj7g0+2U0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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