SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b77506d776e514bcaa85289d8f0b669580975ab52b790ebb18267aada5a1f23' 
  AND token = 'Pz620LYnUkQVFXVkWuf4ZnEoyvIEKpWThfSm1l2kdTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}