SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '435b0f8a95e9b5a6b9e9f6cf72115e29d35f6e43900e5a010a9e4d8ed3949632' 
  AND token = 'OpUNmP3ywosi8VpCryGunmYMmDFoOcfqn85DvWwcTx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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