SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd3a8d37f1f4583862d9da1e5937fe8d6a7c9496c69c5b8446677647de597772' 
  AND token = 'GaXeMwq8zYyRBx0fuxfOFhpVkIsKsjgbbZA1V71BN9s=' 
  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"
    }
  }
}